Collapsible lens barrel and optical instrument using the same

ABSTRACT

A collapsible lens barrel includes a first holding frame ( 2 ) for holding a first lens group (L 1 ), a second holding frame ( 5 ) for holding a second lens group (L 2 ) that is disposed on an image plane side with respect to the first lens group (L 1 ), an actuator ( 6 ) for moving the second holding frame  5  in an optical axis direction, and a tubular cam frame ( 17 ) including a plurality of cam grooves that are formed at substantially equal intervals around a circumferential direction for moving the first holding frame ( 2 ) in the optical axis direction. The actuator ( 6 ) is attached to a portion in the cam frame ( 17 ) where the cam grooves are not formed. The first lens group (L 1 ) is moved using the cam grooves, and the second lens group (L 2 ) is moved using the actuator ( 6 ), so that a faster zooming speed and a lower zooming noise can be achieved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 12/370,366,which is a Division of application Ser. No. 11/978,429 filed Oct. 29,2007, which is a Continuation of application Ser. No. 10/528,977, filedMar. 22, 2005, which is a U.S. National Stage application ofPCT/JP2003/012116, filed Sep. 22, 2003, which applications areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a collapsible lens barrel forhigh-factor zooming. In particular, the present invention relates to acollapsible lens barrel capable of improving a zoom operability,miniaturizing a lens barrel and reducing an entire length of the lensbarrel while maintaining its optical performance. Also, the presentinvention relates to an optical instrument using such a collapsible lensbarrel.

BACKGROUND ART

In recent years, the use of a digital still camera (in the following,referred to as DSC) allowing a user to check a captured imageimmediately has been expanding rapidly. As a lens barrel for this DSC, aso-called collapsible lens barrel, which can be made shorter when not inuse, generally is adopted in view of its portability when not in use.

FIG. 35 is an exploded perspective view showing a conventionalcollapsible lens barrel (see JP 2002-107598 A, for example). Thiscollapsible lens barrel 60 is an optical system in which a single cambarrel 61 moves moving lens frames 62 and 63 back and forth so as tochange a focal length. The inner peripheral surface of this cam barrel61 is provided with cam grooves 64 and 65, which determine moving pathsof the moving lens frames 62 and 63, respectively. Three cam pins 62 aprovided on the outer peripheral surface of the moving lens frame 62 andthree cam pins 63 a provided on the outer peripheral surface of themoving lens frame 63 mate with the cam grooves 64 and 65, respectively,whereby the moving lens frames 62 and 63 move in an optical axis(Z-axis) direction. The cam barrel 61 is provided outside a fixed barrel70 and can rotate freely around the optical axis. An outer periphery ofthe cam barrel 61 is provided with a gear 66, which engages with adriving force transmitting gear 67. The driving force transmitting gear67 is connected to an output axis of a cam barrel driving actuator 69via a reduction gear train 68. Thus, when the cam barrel drivingactuator 69 is driven, the driving force is transmitted via thereduction gear train 68 to the driving force transmitting gear 67,thereby rotating the cam barrel 61. This moves the moving lens frames 62and 63 along respective shapes of the cam grooves 64 and 65, so thatzooming is carried out from a collapsed state via a wide angle end.

FIG. 36 is a development showing the cam grooves 64 and 65 formed on theinner peripheral surface of the cam barrel 61. As shown in FIG. 36, thecam grooves 64 and 65 are formed in a circumferential direction of thecam barrel 61 so as to extend from a collapsed position through a wideangle end position to a telephoto end position. Accordingly, when thepower of DSC is turned on, the moving lens frames 62 and 63 shift fromthe collapsed position to the wide angle end position, which is the nextstop position, and stop there for an image capturing.

Further, with an increase in the optical zooming factor, the influenceof camera shake has become conspicuous. In order to reduce thisinfluence, a DSC including an image blurring correcting device is on itsway to becoming commercialized. As this image blurring correcting devicefor DSC, there has been a suggested method of moving a correcting lensgroup in two directions that are perpendicular to the optical axis so asto correct the camera shake by a user, thereby obtaining a stable image(see JP 2001-117129 A, for example).

However, in the conventional collapsible lens barrel described above,since the reduction gear train 68 and the cam frame (cam barrel 61) areused for zooming, there have been problems in that an increase in a zoomspeed and a reduction in a zoom noise are difficult to achieve.

DISCLOSURE OF INVENTION

Accordingly, the object of the present invention is to provide acollapsible lens barrel capable of increasing the zoom speed andreducing the zoom noise while being ready for a high zooming factor.Further, the object of the present invention is to provide an opticalinstrument including such a collapsible lens barrel.

In order to achieve the above-mentioned objects, a collapsible lensbarrel according to the present invention includes a first holding framefor holding a first lens group, a second holding frame for holding asecond lens group that is disposed on an image plane side with respectto the first lens group, an actuator for moving the second holding framein an optical axis direction, and a tubular cam frame including aplurality of cam grooves that are formed at substantially equalintervals around a circumferential direction for moving the firstholding frame in the optical axis direction. The actuator is attached toa portion in the cam frame where the cam grooves are not formed.

A first optical instrument according to the present invention is anoptical instrument to which the above-described collapsible lens barrelaccording to the present invention is attached, and includes a storingsystem capable of storing an optical zooming factor at a time of turningoff a power as an initial optical zooming factor information. In thecase where the initial optical zooming factor information is stored inthe storing system, the second lens group is moved to and stopped at anoptical zooming factor position based on the initial optical zoomingfactor information when the power is turned on.

Further, a second optical instrument according to the present inventionis an optical instrument to which the above-described collapsible lensbarrel according to the present invention is attached, and includes aninput system for inputting an optical zooming factor at a time ofturning on a power, and a storing system for storing the optical zoomingfactor inputted from the input system as an initial optical zoomingfactor information. In the case where the initial optical zooming factorinformation is stored in the storing system, the second lens group ismoved to and stopped at an optical zooming factor position based on theinitial optical zooming factor information when the power is turned on.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing a collapsible lens barrelaccording to a first embodiment of the present invention.

FIG. 2A is a half sectional view showing how to mold a fixing portion ina first group moving frame for fixing a guide pole in the collapsiblelens barrel according to the first embodiment of the present invention.FIG. 2B is a half sectional view showing how the guide pole is pressfitted and fixed into the fixing portion formed in the first groupmoving frame in the collapsible lens barrel according to the firstembodiment of the present invention. FIG. 2C is a half sectional viewshowing how to fix a conventional guide pole.

FIG. 3 is an exploded perspective view for describing guide polesupporting portions in the collapsible lens barrel according to thefirst embodiment of the present invention.

FIG. 4A shows a lens tilt in an ideal collapsible lens barrel, FIG. 4Bshows a lens tilt in a conventional collapsible lens barrel, and FIG. 4Cshows a lens tilt in the collapsible lens barrel according to the firstembodiment of the present invention.

FIG. 5 is a development of cam grooves in the collapsible lens barrelaccording to the first embodiment of the present invention.

FIG. 6A is a partially sectional view taken in a plane parallel with anoptical axis, showing how a cam pin and a cam groove mate with eachother in the collapsible lens barrel according to the first embodimentof the present invention. FIG. 6B is a partially sectional view taken inthe plane parallel with the optical axis, showing how the cam pin andthe cam groove mate with each other in a wide portion of the cam groovein the collapsible lens barrel according to the first embodiment of thepresent invention.

FIG. 7 is an exploded perspective view for describing a mountingposition of a home position detecting sensor of a second group lens inthe collapsible lens barrel according to the first embodiment of thepresent invention.

FIG. 8 is an exploded perspective view showing a configuration of animage blurring correcting device in the collapsible lens barrelaccording to the first embodiment of the present invention.

FIG. 9 shows the relationship between a displaced amount of a positiondetecting portion of the image blurring correcting device and a magneticflux density in the collapsible lens barrel according to the firstembodiment of the present invention.

FIG. 10 is a block diagram for describing an operation of the imageblurring correcting device in the collapsible lens barrel according tothe first embodiment of the present invention.

FIG. 11 is an exploded perspective view showing a cam frame in thecollapsible lens barrel according to the first embodiment of the presentinvention.

FIG. 12 is a block diagram showing a configuration of an actuatordriving circuit in an optical instrument according to the firstembodiment of the present invention.

FIG. 13 a block diagram showing a hardware configuration of an imageprocessing portion in the optical instrument according to the firstembodiment of the present invention.

FIG. 14 is a schematic view showing an operating portion of the opticalinstrument according to the first embodiment of the present invention.

FIG. 15 is a flowchart showing a method for assembling the collapsiblelens barrel according to the first embodiment of the present invention.

FIG. 16 is a perspective view for describing a first assembling step inthe method for assembling the collapsible lens barrel according to thefirst embodiment of the present invention.

FIG. 17 is a perspective view for describing a second assembling step inthe method for assembling the collapsible lens barrel according to thefirst embodiment of the present invention.

FIG. 18 is a perspective view for describing a third assembling step inthe method for assembling the collapsible lens barrel according to thefirst embodiment of the present invention.

FIG. 19 is a perspective view for describing a fourth assembling step inthe method for assembling the collapsible lens barrel according to thefirst embodiment of the present invention.

FIG. 20 is a sectional view for describing how the cam pin and the camgroove mate with each other in the fourth assembling step in thecollapsible lens barrel according to the first embodiment of the presentinvention.

FIG. 21 is a perspective view for describing how to fix a flexible printcable in the method for assembling the collapsible lens barrel accordingto the first embodiment of the present invention.

FIG. 22 is a sectional view showing the collapsible lens barrel when itis collapsed according to the first embodiment of the present invention.

FIG. 23 is a sectional view showing the collapsible lens barrel when itis used at a telephoto end according to the first embodiment of thepresent invention.

FIG. 24 is a sectional view showing the collapsible lens barrel when itis used at a wide angle end according to the first embodiment of thepresent invention.

FIG. 25 is a sectional view showing the collapsible lens barrel when itis used at an intermediate position between the wide angle end and thetelephoto end according to the first embodiment of the presentinvention.

FIGS. 26A to 26C are drawings for describing images captured atpredetermined zooming factors using the optical instrument according tothe first embodiment of the present invention.

FIG. 27 is a sectional view showing a cam frame in a collapsible lensbarrel according to a second embodiment of the present invention.

FIG. 28 is a sectional side view showing an arrangement of a front endof a second group lens driving actuator in a collapsible lens barrelaccording to a third embodiment of the present invention.

FIG. 29 is a block diagram showing a configuration of an actuatordriving circuit in an optical instrument according to a fourthembodiment of the present invention.

FIG. 30 is a block diagram showing a configuration of an actuatordriving circuit in an optical instrument according to a fifth embodimentof the present invention.

FIG. 31 is a schematic view showing an operating panel in a zoom initialposition selecting system in the optical instrument according to thefifth embodiment of the present invention.

FIG. 32 is an exploded perspective view for describing the positionalrelationship between a driving gear and an image blurring correctingdevice in a collapsible lens barrel according to a sixth embodiment ofthe present invention.

FIG. 33 is a front view seen from a direction parallel with an opticalaxis, showing the driving gear and the image blurring correcting devicein the collapsible lens barrel according to the sixth embodiment of thepresent invention.

FIG. 34 is an exploded perspective view for describing the positionalrelationship between a shutter unit and a second group moving frame in acollapsible lens barrel according to a seventh embodiment of the presentinvention.

FIG. 35 is an exploded perspective view showing a conventionalcollapsible lens barrel.

FIG. 36 is a development showing a cam groove formed on an innerperipheral surface of a cam barrel of the conventional collapsible lensbarrel.

BEST MODE FOR CARRYING OUT THE INVENTION

A collapsible lens barrel according to the present invention includes afirst holding frame for holding a first lens group, a second holdingframe for holding a second lens group that is disposed on an image planeside with respect to the first lens group, an actuator for moving thesecond holding frame in an optical axis direction, and a tubular camframe including a plurality of cam grooves that are formed atsubstantially equal intervals around a circumferential direction formoving the first holding frame in the optical axis direction. Theactuator is attached to a portion in the cam frame where the cam groovesare not formed.

In accordance with the collapsible lens barrel of the present inventiondescribed above, the first lens group is driven via the cam grooves, andthe second lens group is driven via the actuator. Since the first lensgroup and the second lens group are driven separately in this manner,the first lens group does not have to be driven when driving the secondlens group for zooming. Therefore, it is possible to achieve acollapsible lens barrel capable of increasing the zoom speed andreducing the zoom noise. Accordingly, a user can change the angle ofview instantly, making it possible to chase a subject, capture a movingimage, etc., which have been difficult in conventional DSCs.

Further, since the actuator for driving the second lens group isprovided on the cam frame without interfering with the plurality of camgrooves, it is possible to reduce the number of components thanks to ahigh-density mounting, reduce the diameter of the lens barrel, simplifythe configuration and lower costs.

The above-described collapsible lens barrel according to the presentinvention further may have a detecting member for detecting a positionof the second holding frame, a substantially hollow cylindrical drivingframe that is rotatable around an optical axis and moves together withthe first holding frame in the optical axis direction, and a drivinggear for rotating the driving frame. In this case, it is preferable thatthe cam grooves mate with the driving frame, and the driving frame movesin the optical axis direction along the cam grooves with a rotation ofthe driving frame. It also is preferable that the detecting member andthe driving gear respectively are attached to the portion in the camframe where the cam grooves are not formed.

With this preferable mode, since the position detecting member for thesecond lens group and the driving gear for rotating the driving frameare provided on the cam frame without interfering with the plurality ofcam grooves, it is possible to reduce the number of components thanks toa high-density mounting, reduce the diameter of the lens barrel,simplify the configuration and lower costs.

In the above-described collapsible lens barrel according to the presentinvention, it is preferable that the cam frame is molded out of a resinby using a molding die, which is a combination of a plurality of moldingdie parts, and at least one of the plurality of cam grooves formed onthe cam frame and at least one of mounting portions of the actuator, thedetecting member and the driving gear are molded with a common moldingdie part.

With this preferable mode, since the number of molding die parts forresin-molding can be reduced, it is possible to reduce the costs of themolding die and thus lower the costs of the lens barrel.

The above-described collapsible lens barrel according to the presentinvention further may have at least two rod-like guide members parallelwith each other whose one end is fixed to the first holding frame. Inthis case, it is preferable that the second holding frame is heldslidably by the guide members.

With this preferable mode, when the first lens group tilts with respectto the optical axis, the second lens group also tilts in the samedirection. Accordingly, the reduction of optical performance can besuppressed.

In this case, the collapsible lens barrel according to the presentinvention further may have an image blurring correcting member forholding a third lens group for correcting image blurring disposed on theimage plane side with respect to the second holding frame. In this case,it is preferable that the guide members are supported in such a manneras to be slidable with respect to the image blurring correcting membersubstantially in parallel with the optical axis.

With this preferable mode, the directions in which the first and secondlens groups tilt with respect to the third lens group for correctingimage blurring, which have the greatest influence on the opticalperformance, can be aligned, thereby suppressing the reduction ofoptical performance further.

Also, it is preferable that each of the guide members is fixed to thefirst holding frame by being press-fitted into two through holespenetrating in the optical axis direction that are spaced from eachother.

With this preferable mode, it is easy to adjust the degree ofparallelization of the guide members with respect to the optical axis,so that the guide members can be fixed in parallel with the opticalaxis. Also, the number of assembling steps can be reduced compared withthe conventional system of pre-fixing the guide member with a jigintended for this purpose and adhering it.

In the above-described collapsible lens barrel according to the presentinvention, it is preferable that a gap is provided between the firstlens group and the first holding frame in a direction perpendicular toan optical axis, and the first lens group and the first holding framemove toward the image plane side and a front end of the actuator entersthe gap at a time of non-capturing.

With this preferable mode, the entire length of a collapsed lens barrelcan be reduced without increasing the diameter of the lens barrel.

The above-described collapsible lens barrel according to the presentinvention further may have a substantially hollow cylindrical drivingframe that rotates around an optical axis relative to the cam frame,thereby moving together with the first holding frame in the optical axisdirection. In this case, it is preferable that the driving frameincludes mating members for mating with the cam grooves, and wideportions whose width along the optical axis direction is increased areformed in the cam grooves so that the mating members do not contact thecam grooves when the first lens group is moved furthest to the imageplane side.

With this preferable mode, even when a compression load in the opticalaxis direction is applied in a collapsed state, the mating members donot contact the cam grooves. Therefore, it is possible to prevent damageto the lens barrel such as the deformation of the mating members or thedamage to the cam grooves.

It is preferable that the above-described collapsible lens barrelaccording to the present invention further includes a detecting memberdisposed for detecting an absolute position of the second holding framein the optical axis direction when the second holding frame is at aposition furthest to the image plane side or in the vicinity thereof.

With this preferable mode, since the zooming position information afterturning on the power can be detected and initialized instantly, it ispossible to shorten the time required for shifting to the next zoomingposition.

Here, it is preferable that the position furthest to the image planeside substantially is a telephoto end position in an optical system.

With this preferable mode, the zooming position after turning on thepower can be shifted instantly to the vicinity of the telephoto endposition not through the wide angle end. This allows a user to scale upan image without missing an important shutter chance.

Also, the image blurring correcting member may include a pair ofactuators for driving the third lens group in two directionsperpendicular to the optical axis. In this case, it is preferable thatthe driving gear for rotating the driving frame is disposed between thepair of actuators.

With this preferable mode, since the driving gear is provided betweenthe pair of actuators for correcting image blurring, it becomes possibleto bring the driving gear toward the center of the optical axis withoutcausing interference with the cam grooves. Consequently, the diameter ofthe lens barrel can be reduced.

The above-described collapsible lens barrel according to the presentinvention further may include a shutter unit between the image blurringcorrecting member and the second holding frame. In this case, it ispreferable that the shutter unit includes a driving actuator on itssurface on the side of the second holding frame, and the second holdingframe is provided with a recessed portion that the driving actuatorpartially enters.

With this preferable mode, it is possible to reduce the clearancebetween the shutter unit and the second holding frame, therebyshortening the entire length of the collapsible lens barrel.

Although there is no particular limitation on a method for assemblingthe above-described collapsible lens barrel according to the presentinvention, this collapsible lens barrel can be assembled as follows, forexample. That is, the method may include a first assembling step ofassembling the first holding frame and the driving frame, a secondassembling step of assembling the driving frame and the cam frame whileallowing the mating members and the cam grooves to mate with each other,a third assembling step of moving the mating members of the drivingframe to the wide portions of the cam grooves and a fourth assemblingstep of fixing a fixing frame to the cam frame. Here, the fixing frameis a frame on which a driving means for moving the first holding framein the optical axis direction is mounted, though no driving means needbe mounted yet in the fourth assembling step. In addition, all of thefirst to fourth assembling steps are carried out from the samedirection.

With this method for assembling a collapsible lens barrel, since all thecomponents are installed from the same direction, it is possible toreduce the number of assembling steps and lower the cost of the lensbarrel.

Also, since the fourth assembling step fixes the fixing frame to the camframe while the mating members are already moved to the wide portions ofthe cam grooves, the mating members and the cam grooves do not contacteach other even when a compression load in the optical axis direction isapplied to the barrel in the fourth assembling step, and problems suchas deformation of the mating members or damages to the cam grooves arenot caused.

Next, a first optical instrument according to the present invention isan optical instrument to which the above-described collapsible lensbarrel according to the present invention is attached, and includes astoring system capable of storing an optical zooming factor at a time ofturning off a power as an initial optical zooming factor information. Inthe case where the initial optical zooming factor information is storedin the storing system, the second lens group is moved to and stopped atan optical zooming factor position based on the initial optical zoomingfactor information when the power is turned on.

With this first optical instrument, when the power is turned off, a setvalue of the last zooming position used is stored automatically. Thus,the next time the power is turned on, it is possible to start capturingimages at the same angle of view.

Further, a second optical instrument according to the present inventionis an optical instrument to which the above-described collapsible lensbarrel according to the present invention is attached, and includes aninput system for inputting an optical zooming factor at a time ofturning on a power, and a storing system for storing the optical zoomingfactor inputted from the input system as an initial optical zoomingfactor information. In the case where the initial optical zooming factorinformation is stored in the storing system, the second lens group ismoved to and stopped at an optical zooming factor position based on theinitial optical zooming factor information when the power is turned on.

With this second optical instrument, since the zooming factor at thetime of turning on the power can be set freely by a user, it becomespossible to change the zooming factor depending on the scene orsituation of image capturing. Consequently, it is less likely that aproblem of missing a shutter chance is caused.

The following is a description of the present invention with referenceto specific embodiments. However, the present invention is not limitedto the embodiments described below.

First Embodiment

In the following, a collapsible lens barrel according to the firstembodiment of the present invention will be described, with reference toFIGS. 1 to 26.

As shown in FIG. 1, an XYZ three-dimensional rectangular coordinatesystem is set, with an optical axis of a collapsible lens barrel 1 beinga Z axis (an object side being a positive side). L1 denotes a firstgroup lens, L2 denotes a second group lens that moves along an opticalaxis (Z axis) for zooming, L3 denotes a third group lens for correctingan image blurring, and L4 denotes a fourth group lens that moves alongthe optical axis for correcting an image plane fluctuation caused byzooming and for achieving focus.

A first group holding frame 2 holds the first group lens L1 and is fixedto a tubular first group moving frame 3 with a screw or the like suchthat a center axis of the first group lens L1 is parallel with theoptical axis. One end of each of two guide poles (guide members) 4 a and4 b parallel to the optical axis is fixed to this first group movingframe 3. How to fix these guide poles 4 will be described later.

A second group moving frame 5 holds the second group lens L2 and issupported by the above-mentioned two guide poles 4 a and 4 b so as to beslidable in the optical axis direction. Further, a feed screw 6 a of asecond group lens driving actuator 6 such as a stepping motor and ascrew portion of a rack 7 provided in the second group moving frame 5engage with each other, whereby the driving force of the second grouplens driving actuator 6 causes the second, group moving frame 5 to movein the optical axis direction for zooming.

A third group frame 8 holds an image blurring correcting lens group L3(a third group lens) and constitutes an image blurring correcting device31, which will be described later.

A fourth group moving frame 9 is supported by two guide poles 11 a and11 b that are parallel with the optical axis and interposed between thethird group frame 8 and a master flange 10, so that the fourth groupmoving frame 9 is slidable in the optical direction. Moreover, a feedscrew 12 a of a fourth group lens driving actuator 12 such as a steppingmotor and a screw portion of a rack 13 provided in the fourth groupmoving frame 9 engage with each other, whereby the driving force of thefourth group lens driving actuator 12 causes the fourth group movingframe 9 to move in the optical axis direction for correcting the imageplane fluctuation due to zooming and for achieving focus.

An imaging element (CCD) 14 is attached to the master flange 10.

Herein, how to fix the guide poles 4 a and 4 b to the first group movingframe 3 will be described referring to FIGS. 2A to 2C. Each of FIGS. 2Ato 2C is a half sectional view showing one side alone with respect tothe Z axis. Although the following description is directed to how to fixthe guide pole 4 a on one side with respect to the Z axis to a fixingportion 3 e, the same applies to the case of fixing the guide pole 4 bon the other side to the fixing portion.

FIG. 2A is a half sectional view showing a method for molding out of aresin the fixing portion 3 e for fixing one end of the guide pole 4 a.As shown in FIG. 2A, the fixing portion 3 e for fixing one end of theguide pole 4 a is formed on an inner surface of the first group movingframe 3 by molding. The fixing portion 3 e substantially is parallelwith the Z axis and formed of through holes 3 e ₁ and 3 e ₂ that arespaced from each other. These through holes 3 e ₁ and 3 e ₂ are moldedout of a resin using three molding dies 29 a, 29 b and 29 c. Theresin-molding is performed while keeping the columnar molding dies 29 aand 29 b in contact with both lateral surfaces of the molding die 29 chaving a substantially trapezoidal cross-section. Thereafter, thecolumnar molding dies 29 a and 29 b are pulled out in oppositedirections A and B that are substantially parallel with the Z axis andthe substantially trapezoidal molding die 29 c is pulled out in adirection C approaching the Z axis, thereby obtaining the through holes3 e ₁ and 3 e ₂. At this time, the positions of the columnar moldingdies 29 a and 29 b within a plane perpendicular to the Z axis areadjusted so that the guide pole 4 a may be fixed in parallel with the Zaxis when it is press-fitted into the through holes 3 e ₁ and 3 e ₂.

Subsequently, as shown in FIG. 2B, the guide pole 4 a is press-fittedinto the through holes 3 e ₁ and 3 e ₂ from the right side of the figure(the side of the imaging element 14). Although inner diameters d₁ and d₂of the through holes 3 e ₁ and 3 e ₂ are set to be larger than an outerdiameter D of the guide pole 4 a by several micrometers, the guide pole4 a is fixed firmly by the two through holes 3 e ₁ and 3 e ₂ owing to arelative displacement or tilt of center axes 30 a and 30 b of thecolumnar molding dies 29 a and 29 b (see FIG. 2A) within the planeperpendicular to the Z axis. In this manner, the guide pole 4 a is fixedto the first group moving frame 3 so as to be parallel with the Z axis.

FIG. 2C is a half sectional view showing a conventional method forfixing the guide pole 4 a. The conventional fixing method is as follows.First, a fixing portion 3 d formed of a single continuous through holehaving an inner diameter d₃ that is sufficiently larger than the outerdiameter D of the guide pole 4 a is molded out of a resin. Next, theguide pole 4 a is inserted into the fixing portion 3 d, pre-fixed with ajig intended for this purpose and fixed by filling an adhesive betweenthe guide pole 4 a and the fixing portion 3 d.

As described above, in the method for fixing the guide pole according tothe present embodiment, the guide pole 4 a can be fixed in parallel withthe Z axis simply by press-fitting the guide pole 4 a into the throughholes 3 e ₁ and 3 e ₂. Thus, unlike the conventional case, there is noneed for a jig specifically for pre-fixing the guide pole 4 a or anadhesive. Also, time and trouble in curing the adhesive are not needed.Consequently, it is possible to fix the guide pole 4 a at a low cost andwithin a short time. Furthermore, simply by adjusting the positions ofthe molding dies 29 a and 29 b within the plane perpendicular to the Zaxis, the guide pole 4 a can be fixed precisely in parallel with the Zaxis.

Next, how to support the guide poles 4 a and 4 b will be describedreferring to FIG. 3.

The third group frame 8 is provided with a supporting portion 8 a (on amain axis side) and a supporting portion 8 b (on a rotation stopperside). The guide poles 4 a and 4 b penetrate through the supportingportions 8 a and 8 b, so that they are held in parallel with the opticalaxis. Since the guide poles 4 a and 4 b slide in the optical axisdirection with respect to these two supporting portions 8 a and 8 b, thefirst group lens L1 held by the first group moving frame 3 fixed to oneend of each of the guide poles 4 a and 4 b maintains its precision withrespect to the image blurring correcting lens L3 provided in the thirdgroup frame 8. Furthermore, the guide poles 4 a and 4 b slidablypenetrate through a supporting portion 5 a (on the rotation stopperside) and a supporting portion 5 b (on the main axis side) that areprovided in the second group moving frame 5, whereby the second groupmoving frame 5 is supported slidably in the optical axis direction bythe guide poles 4 a and 4 b. Consequently, the second group lens L2 heldby the second group moving frame 5 maintains its precision with respectto the image blurring correcting lens L3 provided in the third groupframe 8.

Herein, the relationship among the first group lens L1, the second grouplens L2 and the third group lens L3 mentioned above will be describedreferring to FIGS. 4A to 4C. In these figures, arrows L1 a and L2 aindicate directions of center axes of the first group lens L1 and thesecond group lens L2, respectively.

FIG. 4A shows an ideal state of the three lens groups L1, L2 and L3, inwhich the center axis L1 a of the first group lens L1 and the centeraxis L2 a of the second group lens L2 are parallel with the Z axis(which is the optical axis of the lens barrel and corresponds to thecenter axis of the third group lens L3).

FIG. 4B shows the case in which the first group lens L1 and the secondgroup lens L2 are supported respectively by the cam pin 62 a provided inthe moving lens frame 62 and the cam pin 63 a provided in the movinglens frame 63 shown in FIG. 35 by a system similar to the conventionallens barrel shown in FIG. 35. In this case, because of a variation inprecision of the cam pins 62 a and 63 a and the cam grooves 64 and 65,the center axis L1 a of the first group lens L1 and the center axis L2 aof the second group lens L2 are neither parallel with each other norparallel with the Z axis. Thus, it is likely that the opticalperformance will deteriorate.

FIG. 4C shows the case according to the present embodiment. The firstgroup lens L1 and the second group lens L2 are supported by the sameguide poles 4 a and 4 b. Therefore, even when the center axis L1 a ofthe first group lens L1 and the center axis L2 a of the second grouplens L2 tilt with respect to the Z axis, the directions of these centeraxes Ma and L2 a always coincide with each other. In other words, sincethe first group lens L1 and the second group lens L2 always tilt in thesame direction with respect to the image blurring correcting lens groupL3, which has the greatest influence on the optical performance, it ispossible to minimize the deterioration of the optical performance.

Next, the configuration of moving the first group lens L1 in the opticalaxis direction will be described.

As shown in FIG. 1, a gear 15 a is formed in a part of an innerperipheral surface of a substantially hollow cylindrical driving frame15 on the side of the imaging element 14. Also, three protrudingportions 15 b are formed at substantially 120° intervals on the innerperipheral surface thereof on the object side (the positive side of theZ axis). The protruding portions 15 b mate with three circumferentialgroove portions 3 a provided in an outer peripheral surface of the firstgroup moving frame 3 on the side of the imaging element 14, whereby thedriving frame 15 can rotate relative to the first group moving frame 3around the optical axis, and the driving frame 15 and the first groupmoving frame 3 move integrally in the optical axis direction.Furthermore, three cam pins 16 a, 16 b and 16 c are press-fitted andfixed to the inner peripheral surface of the driving frame 15 at 120°intervals.

On an outer surface of a tubular cam frame 17, three cam grooves 18 a,18 b and 18 c are formed at substantially 120° intervals. FIG. 5 is adevelopment of the outer peripheral surface of the cam frame 17. The campins 16 a, 16 b and 16 c of the driving frame 15 mate with the camgrooves 18 a, 18 b and 18 c of the cam frame 17, respectively. Each ofthe cam grooves 18 a, 18 b and 18 c has a portion 19 a that issubstantially parallel with the circumferential direction of the camframe 17 on the side of the imaging element 14 (the negative side of theZ axis), a portion 19 c that is substantially parallel with thecircumferential direction of the cam frame 17 on the object side (thepositive side of the Z axis), a portion 19 b that connects spirally theportion 19 a and the portion 19 c and a wide portion 19 d whose widthincreases in the Z-axis direction at the end of the portion 19 a. Whenthe cam pins 16 a, 16 b and 16 c are located in the portion 19 a, thefirst group lens L1 stops while being retracted toward the side of theimaging element 14 (a collapsed state). From this state, the drivingframe 15 rotates around the optical axis, so that the cam pins 16 a, 16b and 16 c move through the portion 19 b and reach the portion 19 c.When the cam pins 16 a, 16 b and 16 c are located in the portion 19 c,the first group lens L1 stops while being advanced toward the objectside.

The cam grooves 18 a, 18 b and 18 c are formed so as to have differentwidths along the optical axis direction depending on how far the drivingframe 15 is advanced. This will be described referring to FIG. 6.

FIG. 6A is a partially sectional view taken in a direction parallel withthe Z axis, showing the cam pins 16 a, 16 b and 16 c and the cam grooves18 a, 18 b and 18 c in the portions 19 a, 19 b and 19 c of the camgrooves 18 a, 18 b and 18 c. As shown in the figure, in the portions 19a, 19 b and 19 c, the cam grooves 18 a, 18 b and 18 c are formed to beabout several micrometers wider than the cam pins 16 a, 16 b and 16 calong the Z-axis direction. As a result, the cam pins 16 a, 16 b and 16c can slide smoothly in the cam grooves 18 a, 18 b and 18 c.

FIG. 6B is a partially sectional view taken in the direction parallelwith the Z axis, showing the cam pins 16 a, 16 b and 16 c and the camgrooves 18 a, 18 b and 18 c in the wide portions 19 d of the cam grooves18 a, 18 b and 18 c. As shown in the figure, in the wide portions 19 d,the cam grooves 18 a, 18 b and 18 c are formed to be wider than the campins 16 a, 16 b and 16 c along the Z-axis direction so that the cam pins16 a, 16 b and 16 c do not contact the cam grooves 18 a, 18 b and 18 cin the Z-axis direction. As a result, in the state where the drivingframe 15 is retracted furthest to the image plane side (the state inFIG. 22 described later), the cam pins 16 a, 16 b and 16 c are locatedin the wide portions 19 d and do not contact the cam grooves 18 a, 18 band 18 c as shown in FIG. 6B.

On the outer peripheral surface of the cam frame 17, a bearing portion17 d for holding driving gear shafts 20 at both ends of a spline-likedriving gear 19 rotatably and a driving gear mounting portion (arecessed portion) 17 a that is recessed in a hemicylindrical shape foravoiding an interference with the driving gear 19 are formed between thecam grooves 18 b and 18 c, whereby the driving gear 19 is held rotatablyon the outer peripheral surface of the cam frame 17. The driving gear 19transmits a driving force of a driving unit 21, which will be describedlater, mounted to the master flange 10 to a gear portion 15 a providedin the driving frame 15. Accordingly, the rotation of the driving gear19 causes the driving frame 15 to rotate around the optical axis. Atthis time, the cam pins 16 a, 16 b and 16 c provided in the drivingframe 15 move in the cam grooves 18 a, 18 b and 18 c of the cam frame17, whereby the driving frame 15 moves also in the optical axisdirection. Here, since the two guide poles 4 a and 4 b fixed to thefirst group moving frame 3 penetrate through the supporting portions 8 aand 8 b of the third group frame 8, the rotation of the first groupmoving frame 3 around the optical axis is restricted, so that the firstgroup moving frame 3 moves straight along the optical axis direction asthe driving frame 15 moves along the optical axis direction.

The driving actuator 6 of the second group moving frame 5 is fixed to amounting portion 17 b of the cam frame 17. Also, the driving actuator 12of the fourth group moving frame 9 is fixed to a mounting portion 10 aof the master flange 10. The driving unit 21 for transmitting thedriving force to the driving gear 19 includes a driving actuator 22 anda reduction gear unit 23 constituted by a plurality of gears and isfixed to a mounting portion 10 b of the master flange 10.

A shutter unit 24 is constituted by a diaphragm blade and a shutterblade that form a constant aperture diameter for controlling an exposureamount and an exposure time of the imaging element 14.

A home position detecting sensor 25 for the second group moving frame 5is a photo-detector sensor including a light-emitting element and alight-receiving element and detects the position of the second groupmoving frame 5 in the optical axis direction, namely, a home position(an absolute position) of the second group lens L2. As shown in FIG. 7,this home position detecting sensor 25 is mounted onto an mountingportion 17 c of the cam frame 17 and detects the home position asfollows: when the second group moving frame 5 moves to the positionfurthest to the side of the imaging element 14 (a −Z direction side) orthe vicinity thereof, a blade 5 c provided in the second group movingframe 5 passes in front of the home position detecting sensor 25 andblocks light, thereby allowing the home position to be detected. Whenthe home position is detected, the second group moving frame 5 and therack 7 mounted thereto are located furthest to the side of the imagingelement 14 and close to the driving motor 6. This state corresponds tothat in FIG. 22 described later.

A home position detecting sensor 26 for the fourth group moving frame 9detects the position of the fourth group moving frame 9 in the opticalaxis direction, namely, a home position of the fourth group lens L4. Ahome position detecting sensor 27 for the driving frame 15 detects theposition of the driving frame 15 in a rotational direction, namely, homepositions of the first group moving frame 3 and the first group lens L1that move as one piece with the driving frame 15.

The image blurring correcting device 31 moves the image blurringcorrecting lens group L3 for correcting an image blurring at the time ofimage capturing in a pitching direction, which is a first direction (a Ydirection) and a yawing direction, which is a second direction (an Xdirection). A first electromagnetic actuator 41 y generates a drivingforce in the Y direction, and a second electromagnetic actuator 41 xgenerates a driving force in the X direction, so that the image blurringcorrecting lens group L3 is driven in the X and Y directions that aresubstantially perpendicular to the optical axis Z.

The image blurring correcting device 31 for correcting an image blurringusing the image blurring correcting lens group L3 will be described indetail, referring to FIG. 8.

The image blurring correcting lens group L3 for correcting an imageblurring at the time of image capturing is fixed to a pitching movingframe 32 that is movable in the pitching direction, which is the firstdirection (the Y direction) and the yawing direction, which is thesecond direction (the X direction). This pitching moving frame 32 has abearing 32 a on a −X direction side and a rotation stopper 32 b on a +Xdirection side. A pitching shaft 33 a parallel with the Y-axis directionis inserted into this bearing 32 a and a pitching shaft 33 b parallelwith the Y-axis direction, which will be described later, is allowed tomate with the rotation stopper 32 b, so that the pitching moving frame32 can slide in the first direction (Y direction).

A yawing moving frame 34 for moving the image blurring correcting lensgroup L3 in the second direction (X direction) is provided on the −Zdirection side with respect to the pitching moving frame 32. The yawingmoving frame 34 is provided with fixing portions 34 a that fix both endsof the two pitching shafts 33 a and 33 b for sliding the above-describedpitching moving frame 32 in the pitching direction (Y direction). Also,the yawing moving frame 34 has a bearing 34 b on a +Y direction side anda yawing shaft 35 b and a fixing portion 34 c to which both ends of theyawing shaft 35 b are press-fitted and fixed on a −Y direction side. Ayawing shaft 35 a parallel with the X direction is inserted into thisbearing 34 b and the yawing shaft 35 b parallel with the X direction isallowed to mate with a rotation stopper portion 8 d of the third groupframe 8, so that the yawing moving frame 34 can slide in the seconddirection (X direction).

The third group frame 8 provided on the −Z direction side with respectto the yawing moving frame 34 is provided with a fixing portion 8 c thatfixes the both ends of the yawing shaft 35 a for sliding theabove-described yawing moving frame 34 in the yawing direction (Xdirection) and the rotation stopper portion 8 d with which the yawingshaft 35 b mates.

A substantially L-shaped electric substrate 36 is attached to a −Zdirection side surface of the pitching moving frame 32. The electricsubstrate 36 is provided with a first coil 37 y and a second coil 37 xfor driving the image blurring correcting lens group L3 in the pitchingdirection and the yawing direction, respectively, and Hall elements 38 yand 38 x for detecting the position of the image blurring correctinglens group L3 in the pitching direction and that in the yawingdirection, respectively. These coils 37 y and 37 x are formed as layeredcoils in one piece with the electric substrate 36.

Magnets 39 y and 39 x are two-pole magnetized on one side. These magnets39 y and 39 x respectively are fixed to yokes 40 y and 40 x having asubstantially U-shaped cross-section. The yoke 40 y is fixed to afitting portion 8 y of the third group frame 8 by press-fitting from theY direction. Similarly, the yoke 40 x is fixed to a fitting portion 8 xof the third group frame 8 by press-fitting from the X direction.

The first electromagnetic actuator 41 y includes the first coil 37 y,the magnet 39 y and the yoke 40 y. Similarly, the second electromagneticactuator 41 x includes the second coil 37 x, the magnet 39 x and theyoke 40 x. The first electromagnetic actuator 41 y constitutes a firstdriving means for driving the pitching moving frame 32 in the pitchingdirection (Y direction), which is the first direction, and the secondelectromagnetic actuator 41 x constitutes a second driving means fordriving the pitching moving frame 32 in the yawing direction (Xdirection), which is the second direction.

With the above-described configuration, when an electric current ispassed through the first coil 37 y of the electric substrate 36, themagnet 39 y and the yoke 40 y generate an electromagnetic force alongthe pitching direction (Y direction), which is the first direction. In asimilar manner, when an electric current is passed through the secondcoil 37 x of the electric substrate 36, the magnet 38 x and the yoke 40x generate an electromagnetic force along the yawing direction (Xdirection), which is the second direction. In this way, the twoelectromagnetic actuators 41 y and 41 x drive the image blurringcorrecting lens group L3 in the two directions, i.e., the X directionand the Y direction that are substantially perpendicular to the opticalaxis Z.

The following is a description of position detecting portions 42 y and42 x for detecting the position of the image blurring correcting lensgroup L3. The Hall elements 38 y and 38 x for converting a magnetic fluxinto an electrical signal are positioned and fixed to the electricsubstrate 36. The above-described magnets 39 y and 39 x of theelectromagnetic actuators 41 y and 41 x also serve as detecting magnets.Accordingly, the Hall elements 38 y and 38 x and the magnets 39 y and 39x constitute the position detecting portions 42 y and 42 x. Here,referring to FIG. 9, the state of the magnetic fluxes of the magnets 39x and 39 y will be described. The horizontal axis of the figureindicates a position in the pitching direction (the Y direction) or theyawing direction (the X direction) with the optical axis being thecenter, while the vertical axis indicates a magnetic flux density. Thecenter of the horizontal axis corresponds to a boundary in the two-polemagnetized magnet 39 x or 39 y, and the magnetic flux density is zero atthis position. This position substantially coincides with the center ofthe optical axis of the image blurring correcting lens group L3. TheHall elements 38 y and 38 x move with respect to the magnets 39 y and 39x, whereby the magnetic flux density varies substantially linearly withthe change in a displaced amount within the range that centers on thezero position of the displaced amount and is indicated by broken lines.Thus, by detecting the electric signal outputted from the Hall elements38 y and 38 x, it becomes possible to detect the position of the imageblurring correcting lens group L3 in the pitching direction (the Ydirection) and the yawing direction (the X direction).

A flexible print cable 43 transmits signals between a circuit of acamera main body, which is not shown in the figure, and the coils 37 xand 37 y and the Hall elements 38 x and 38 y that are mounted on theelectric substrate 36.

The elements 32 to 43 described above constitute the image blurringcorrecting device 31.

Now, the following description is directed to an operation of the imageblurring correcting device 31 with reference to FIG. 10.

Image blurring is caused by displacement and vibrations of a camera dueto hand movement. A camera incorporating the image blurring correctingdevice 31 detects these displacement and vibrations with two angularspeed sensors 44 y and 44 x that are disposed so as to have a detectingdirection of substantially 90°. Outputs of the angular speed sensors 44y and 44 x are time-integrated. Subsequently, they are converted into anangle at which the camera main body has moved and then converted intotarget position information of the image blurring correcting lens groupL3. In order to move the image blurring correcting lens group L3according to this target position information, a servo driving circuit45 calculates a difference between the target position information andcurrent positional information of the image blurring correcting lensgroup L3 detected by the position detecting portions 42 y and 42 x andtransmits a signal to the electromagnetic actuators 41 y and 41 x.According to this signal, the electromagnetic actuators 41 y and 41 xdrive the image blurring correcting lens group L3.

With respect to the driving in the pitching direction (Y direction),which is the first direction, the electromagnetic actuator 41 y that hasreceived an instruction from the servo driving circuit 45 passes anelectric current through the first coil 37 y via the flexible printcable 43 so as to generate a force in the pitching direction (Ydirection), thereby driving the pitching moving frame 32 in the pitchingdirection (Y direction).

Also, with respect to the driving in the yawing direction (X direction),which is the second direction, the electromagnetic actuator 41 x thathas received an instruction from the servo driving circuit 45 passes anelectric current through the second coil 37 x via the flexible printcable 43 so as to generate a force in the yawing direction (Xdirection), thereby driving the yawing moving frame 34 and the pitchingmoving frame 32 mounted thereon in the yawing direction (X direction).

In this way, the image blurring correcting lens group L3 can be moved asdesired within a two-dimensional plane perpendicular to the optical axisby the pitching moving frame 32 and the yawing moving frame 34, makingit possible to correct the image blurring caused by camera shake.

Next, positions in the cam frame 17 to which the second group lensdriving actuator 6, the home position detecting sensor 25 and thedriving gear 19 are mounted will be described.

As shown in FIG. 11, the second group lens driving actuator 6 is mountedto the mounting portion 17 b of the cam frame 17. The home positiondetecting sensor 25 of the second group lens L2 is mounted onto themounting portion 17 c of the cam frame 17, and the blade 5 c provided inthe second group moving frame 5 passes in front of the home positiondetecting sensor 25 and blocks light, thereby allowing the home positionto be detected. Further, as described earlier, the driving gear 19 ismounted to the bearing portion 17 d and the driving gear mountingportion (recessed portion) 17 a of the cam frame 17.

FIG. 5 shows the relationship of the three cam grooves 18 a, 18 b and 18c and the three mounting portions 17 a, 17 b and 17 c when they aredeveloped. In other words, the mounting portion 17 a is provided betweenthe cam grooves 18 b and 18 c, the mounting portion 17 b is providedbetween the cam grooves 18 a and 18 b, and the mounting portion 17 c isprovided between the cam grooves 18 c and 18 a. By providing themounting portions 17 a, 17 b and 17 c between these cam grooves in thisway, it becomes possible to mount the driving gear 19, the second grouplens driving actuator 6 and the home position detecting sensor 25 to thecam frame 17 with the mounting portions 17 a, 17 b and 17 c notinterfering with the cam grooves 18 a, 18 b and 18 c.

An actuator driving circuit in an optical instrument (in this case, aDSC 80) including the collapsible lens barrel according to the presentembodiment will be described with reference to FIGS. 12 and 14.

The DSC 80 includes a microcomputer 50 for controlling the DSC 80. Thismicrocomputer 50 drives and controls the first group lens drivingactuator 22 via a driving control system 84 based on a signal from apower source button 81 provided in the DSC 80 and, after the homeposition detecting sensor 27 detects the home position of the firstgroup lens L1, drives the first group lens L1 to a predeterminedposition. Also, the microcomputer 50 drives and controls the secondgroup lens driving actuator 6 via a driving control system 85 based on asignal from a zooming lever 82 and, after the home position detectingsensor 25 detects the home position of the second group lens L2, drivesthe second group lens L2 to a predetermined zoom position. Furthermore,when a shutter button 83 is pressed down, the microcomputer 50 drivesand controls the fourth group lens driving actuator 12 via a drivingcontrol system 86 and, after the home position detecting sensor 26detects the home position of the fourth group lens L4, obtains focus.

Next, an image processing of the DSC 80 will be described referring toFIGS. 13 and 14.

The imaging element (CCD) 14 converts an image entering via thecollapsible lens barrel 1 into an electric signal. An imaging elementdriving control system 143 controls the operation of the imaging element14. An analog signal processing system 144 performs an analog signalprocessing such as a gamma processing with respect to a video signalobtained by the imaging element 14. An A/D converting system 145converts the analog video signal outputted from the analog signalprocessing system 144 into a digital signal. A digital signal processingsystem 146 performs a digital signal processing such as a noise removaland an edge enhancement with respect to the video signal that has beenconverted into the digital signal by the A/D converting system 145. Aframe memory 147 temporarily stores an image signal that has beenprocessed by the digital signal processing system 146. An imagerecording control system 148 controls writing of the image storedtemporarily in the frame memory 147 into an image recording system 149such as an internal memory or a recording medium. According to a signalfrom an image display control system 150, the captured image recorded inthe image recording system 149 is displayed via a frame memory 151 on animage display system 152 such as a liquid crystal monitor mounted on theDSC 80.

The collapsible lens barrel 1 constituted as above can be assembled byfollowing steps S1 to S6 shown in FIG. 15. In the following, each ofthese steps will be described sequentially.

(First Assembling Step S1)

As shown in FIG. 16, the guide poles 4 a and 4 b fixed to the firstgroup moving frame 3 respectively are inserted into the supportingportions 5 a and 5 b of the second group moving frame 5. Further, theprotruding portions 15 b provided in the driving frame 15 are allowed tomate with a groove portion 3 a provided in the first group moving frame3, and then the driving frame 15 is rotated in a direction indicated byan arrow.

(Second Assembling Step S2)

As shown in FIG. 17, the cam pins 16 a, 16 b and 16 c protruding from aninner wall surface of the driving frame 15 are allowed to mate with thecam grooves 18 a, 18 b and 18 c provided on the outer peripheral surfaceof the cam frame 17.

(Third Assembling Step S3)

As shown in FIG. 18, the driving frame 15 is rotated in a directionindicated by an arrow. Since the cam pins 16 a, 16 b and 16 c and thecam grooves 18 a, 18 b and 18 c mate with each other, the rotation ofthe driving frame 15 causes the cam frame 17 to move in the Z-axisdirection and be received in the driving frame 15. The rotation of thedriving frame 15 moves the cam pins 16 a, 16 b and 16 c to the positionsof the wide portions 19 d at terminal ends of the cam grooves 18 a, 18 band 18 c. Next, the guide poles 4 a and 4 b are inserted into thesupporting portions 8 a and 8 b of the third group frame 8 on which theimage blurring correcting device 31 is mounted.

(Fourth Assembling Step S4)

As shown in FIG. 19, after guide poles 11 a and 11 b and the fourthgroup moving frame 9, which are not shown in the figure, are insertedbehind the third group frame 8, the master flange 10 is incorporated.Then, from behind the master flange 10, the cam frame 17, the thirdgroup frame 8 and the master flange 10 are fixed with three screws 135.

Referring to FIG. 20, how the cam pins 16 a, 16 b and 16 c mate with thecam grooves 18 a, 18 b and 18 c in the fourth assembling step will bedescribed. The lens barrel 1 is fastened with screws while keeping anend surface 3 b on the object side of the first group moving frame 3 incontact with a placement surface 180 such that the first group lens L1faces downward. When fastening with screws, a downward load F acts onthe cam frame 17. At this time, the cam pins 16 a, 16 b and 16 c arelocated in the wide portions 19 d at terminal ends of the cam grooves 18a, 18 b and 18 c. Therefore, even under the load F, the cam pins 16 a,16 b and 16 c do not contact the cam grooves 18 a, 18 b and 18 c. Theload F is supported by the contact between an image-plane-side endsurface 3 c of a ring-shaped portion formed so as to protrude from theinner surface of the first group moving frame 3 and an object-side endsurface 17 e of the cam frame 17. Consequently, the load F does not acton the cam pins 16 a, 16 b and 16 c or the cam grooves 18 a, 18 b and 18c at the time of fastening with screws so as to cause problems such asdeformation of the cam pins 16 a, 16 b and 16 c or damage to the camgrooves 18 a, 18 b and 18 c.

(Fifth Assembling Step S5)

The second group lens driving actuator 6 is fixed to the cam frame 17,and the first group lens driving actuator 22 and the fourth group lensdriving actuator 12 are fixed to the master flange 10.

(Sixth Assembling Step S6)

As shown in FIG. 21, the flexible print cable 43 for the image blurringcorrecting device 31 and a flexible print cable 138 for the shutter unit24 are soldered to the electric substrate (a flexible printed circuitboard) 36 attached to the master flange 10 so that soldering portions 36a and 43 a are fixed to each other and soldering portions 36 b and 138 aare fixed to each other. Then, the imaging element 14 is fixed to afixing portion 10 c of the master flange 10.

In the above manner, the assembly of the collapsible lens barrel 1 iscompleted.

In the following, the operation of the collapsible lens barrel 1constituted as above will be explained.

First, in the operation of the collapsible lens barrel 1, an operationof shifting from a non-capturing (non-use) state shown in FIG. 22 via astate shown in FIG. 23 to a capturing (wide angle end) state shown inFIG. 24 will be described.

In the non-capturing state shown in FIG. 22, turning on a power sourceswitch or the like of the DSC 80 starts a state ready for imagecapturing. First, the first group lens driving actuator 22 for drivingthe first group lens L1 rotates, so that the driving gear 19 is rotatedvia the reduction gear unit 23. The rotation of the driving gear 19causes the driving frame 15, which engages with the driving gear 19,both to rotate around the optical axis and to move in the cam grooves 18a, 18 b and 18 c along the optical axis. After the home positiondetecting sensor 27 is initialized, the driving frame 15 moves in anobject direction (the Z-axis direction), whereby the first group movingframe 3 also moves in the object direction. Then, when a rotation amountdetecting sensor, which is not shown in the figure, detects that thefirst group lens driving actuator 22 has moved by a predeterminedrotation amount, the first group moving frame 3 moves to a predeterminedposition, and then the rotation of the first group lens driving actuator22 stops. At this stop position, the cam pins 16 a, 16 b and 16 calready have reached the portion 19 c that is substantially parallelwith the circumferential direction of the cam frame 17 in thedevelopment of the cam grooves in FIG. 5. FIG. 23 shows this state.

Next, in order to move the second group lens L2 serving as a zoominglens to a predetermined position, the second group lens driving actuator6 rotates and drives the rack 7 via the feed screw 6 a, so that thesecond group moving frame 5 starts moving along the Z axis.

First, the description is directed to the case where no initial positionof a zooming factor after turning on the power source is set in themicrocomputer 50 in the DSC 80.

After initializing the home position detecting sensor 25, the secondgroup moving frame 5 moves in the object direction and stops at the wideangle end shown in FIG. 24, so that the camera main body is now able tocapture an image.

On the other hand, in the case where the initial position of the zoomingfactor after turning on the power source is set to the vicinity of atelephoto end in the microcomputer 50 in the DSC 80, after initializingthe home position detecting sensor 25, the second group moving frame 5stops in the vicinity of the telephoto end shown in FIG. 23, so that theDSC 80 becomes ready for image capturing. If the shutter button 83 ispressed down in this state, the image to be captured shows a scaled-upsubject as shown in FIG. 26A.

Further, in the case where the initial position of the zooming factorafter turning on the power source is set to substantially at the midpoint between the telephoto end and the wide angle end in themicrocomputer 50 in the DSC 80, after initializing the home positiondetecting sensor 25, the second group moving frame 5 stops in thevicinity of the mid point shown in FIG. 25, so that the DSC 80 becomesready for image capturing. If the shutter button 83 is pressed down inthis state, the image to be captured is as shown in FIG. 26B.

In the case where the initial position of the zooming factor afterturning on the power source is set to the vicinity of the wide angle endin the microcomputer 50 in the DSC 80, after initializing the homeposition detecting sensor 25, the second group moving frame 5 stops inthe vicinity of the wide angle end shown in FIG. 24, so that the DSC 80becomes ready for image capturing. If the shutter button 83 is presseddown in this state, the image to be captured is as shown in FIG. 26C.

In any of the above cases, the first group moving frame 3 and the secondgroup moving frame 5 move to a predetermined position while beingsupported by the same guide poles 4 a and 4 b held by the supportingportions 8 a and 8 b in the third group frame 8. Accordingly, even whenthe first group lens L1 and the second group lens L2 tilt with respectto the optical axis, a certain optical performance can be securedbecause the directions of the tilt are the same with respect to theimage blurring correcting lens group L3.

At the time of actual image capturing, the second group lens drivingactuator 6 and the fourth group lens driving actuator 12 respectivelyperform a zooming operation and an operation of correcting an imageplane fluctuation due to zooming and achieving focus. When zooming, animage is captured at the wide angle end in the state shown in FIG. 24and at the telephoto end in the state shown in FIG. 23 in which thesecond group lens L2 is moved in a −Z direction (at the end on theimaging element 14 side). Thus, it is possible to capture an image at anarbitrary position from the wide angle end to the telephoto end.

Next, an operation of shifting from each of the capturing states shownin FIGS. 23, 24 and 25 to the non-capturing state shown in FIG. 22 willbe described.

In each of the capturing states, when the power source button 81 in theDSC 80 is switched off, the image capturing ends. The second groupmoving frame 5 first is moved to the side of the imaging element 14 bythe second group lens driving actuator 6, thus creating the state shownin FIG. 23. Subsequently, the first group lens driving actuator 22rotates, thereby rotating the driving gear 19 in a direction opposite tothe above via the reduction gear unit 23. The rotation of the drivinggear 19 causes the driving frame 15, which is in engagement with thedriving gear 19, to rotate around the optical axis, and at the sametime, the cam grooves 18 a, 18 b and 18 c allow the driving frame 15 tomove in the direction of the imaging element 14, so that the first groupmoving frame 3 also moves. Thereafter, when the home position detectingsensor 27 detects the rotation of the driving frame 15, the first groupmoving frame 3 moves to a predetermined position, and then the rotationof the first group lens driving actuator 22 stops. At this stopposition, the cam pins 16 a, 16 b and 16 c already have reached theportion 19 c that is substantially parallel with the circumferentialdirection of the cam frame 17 in the development of the cam grooves inFIG. 5. In this way, a collapsed state shown in FIG. 22 is achieved inwhich the length is reduced by a length C compared with the capturingstate.

Here, in a collapsing operation of changing the length of thecollapsible lens barrel 1 along the optical axis direction, the firstgroup lens driving actuator 22 for driving the first group lens L1 isused. In a zooming operation, the second group lens driving actuator 6is used alone. Thus, since the zooming operation in an actual imagecapturing is carried out with the first group lens L1 being advanced,there is no need to operate the first group lens driving actuator 22,and the second group lens driving actuator 6 alone is driven to move thesecond group lens L2 to a predetermined position between FIG. 23 andFIG. 24 for zooming. Accordingly, when conducting image capturing suchas a zooming operation, it is not necessary to expand and retract abarrel according to a zooming factor unlike the conventional collapsiblelens barrel shown in FIG. 35. In the conventional collapsible lensbarrel shown in FIG. 35, in the zooming operation, one driving actuator69 was rotated, and the cam barrel 61 was rotated via the reduction geartrain 68, thereby driving the moving lens frames 62 and 63 at the sametime, leading to a low zooming speed and a large driving noise. On theother hand, in the collapsible lens barrel 1 according to the presentinvention, a stepping motor is used as the second group lens drivingactuator 6, and the second group moving frame 5 directly is driven viathe feed screw 6 a attached to this stepping motor, achieving a fastfeed speed and a small operation noise. In this manner, even acollapsible lens barrel can achieve a faster zooming speed and a lowerzooming noise. Thus, a user can change the angle of view instantly,making it possible to chase a subject, capture a moving image, etc.,which have been difficult in conventional DSCs.

In the present embodiment, in order to move the second group lens L2 forzooming to a position of a predetermined zooming factor after turning onthe power, the first group lens L1 has to be moved in advance from aposition in the collapsed state to a predetermined position, and acertain time period is required therefor. However, instead of driving aplurality of the moving lens frames 62 and 63 by a single drivingactuator 6 as in the conventional collapsible lens barrel shown in FIG.35, the first group lens L1 and the second group lens L2 are driven byindividual actuators. Thus, one actuator needs only a small drivingforce, and a driving speed (the number of revolutions of the actuator)can be increased, thus making it possible to shorten an entire timeperiod.

As described above, according to the first embodiment, since theactuator 6 specifically for zooming can be attached without interferingwith the cam grooves 18 a, 18 b and 18 c of the cam frame 17, even acollapsible lens barrel can achieve a faster zooming speed and a lowerzooming noise. Thus, a user can change the angle of view instantly,making it possible to chase a subject, capture a moving image, etc.,which have been difficult with conventional DSCs.

According to the present embodiment, the first group lens L1 and thesecond group lens L2 are driven individually. In other words, only thesecond group lens L2 can be driven for zooming. Thus, it is possible toachieve a faster zooming speed and a lower zooming noise. Therefore, ina DSC in which sound is recorded using a microphone while capturing amoving image, for example, a level of recording a zooming noise, whichis not preferable in itself, is lowered, thus improving a commercialvalue considerably.

Further, by disposing not only the actuator 6 for zooming but also thehome position detecting sensor 25 and the driving gear 19 in a portionin the cam frame 17 where the cam grooves 18 a, 18 b and 18 c are notformed, it becomes possible to achieve a high-density mounting thatdisposes all the components in the single cam frame 17, thusminiaturizing the lens barrel, reducing the number of components thanksto a simplified configuration and lowering costs.

Also, in the DSC incorporating a lens ready for a high zooming factor,the home position detecting sensor 25 is disposed so that an absoluteposition of the lens group. L2 for zooming can be detected when thislens is at a collapsed position, in particular, a telephoto end positionor in the vicinity thereof, thus making it possible to move the lensgroup L2 after turning on the power instantly to the vicinity of thetelephoto end position not through the wide angle end. This produces anotable effect of preventing a user from missing an important shutterchance for scaled-up images.

Further, the structure in which the first group lens L1 and the secondgroup lens L2 tilt at least the same direction with respect to the imageblurring correcting lens L3 allows the entire length in non use to bereduced while minimizing the reduction of optical performance.

Furthermore, the guide poles 4 a and 4 b are fixed by being press-fittedinto two through holes penetrating in the optical axis direction thatare spaced from each other, whereby the number of assembling steps canbe reduced compared with the conventional system of pre-fixing the guidepole with a jig intended for this purpose and adhering it. Also, therelative positions of the molding dies 29 a and 29 b forming the throughholes within the plane perpendicular to the Z axis are adjusted, so thatthe orientations of the guide poles 4 a and 4 b can be adjusted easily,making it possible to fix the guide poles 4 a and 4 b in parallel withthe optical axis.

Moreover, in the collapsible lens barrel including the tubular cam frame17 and the substantially hollow cylindrical driving frame 15 providedwith the cam pins 16 a, 16 b and 16 c, the wide portions 19 d are formedin the cam grooves so that the cam pins 16 a, 16 b and 16 c do notcontact the cam grooves 18 a, 18 b and 18 c in the collapsed state.Consequently, even when a compression load in the optical axis directionis applied at the time of the assembly in the collapsed state, problemssuch as deformation of the cam pins 16 a, 16 b and 16 c or damages tothe cam grooves 18 a, 18 b and 18 c are not caused.

Further, even in the collapsible lens barrel using the cam frame 17whose assembly is complicated, by enabling the components to beinstalled and fastened with screws from one direction, it is possible toreduce the number of assembling steps and simplify the assembling workcompared with a conventional method of assembling from both sides.

Although the first group frame 2 provided with the first group lens L1and the first group moving frame 3 are different members in the presentembodiment, they also may be formed as one piece to which the guidepoles may be fixed.

Additionally, in the image blurring correcting device 31 described inthe present embodiment, the position detecting means using the Hallelements also may be provided in other places. Alternatively, a magneticposition detecting means may be replaced by an optical positiondetecting means including a light-emitting element and a light-receivingelement, for example.

Although the third group lens L3 can be moved in a directionperpendicular to the optical axis direction using the image blurringcorrecting device 31, it is needless to say that even a general lensbarrel in which the third group lens L3 is fixed to the third groupframe 8 and no image blurring correcting device is mounted can achieve asimilar effect.

Although the first group moving frame 3 and the second group movingframe 5 are moved sequentially in the present embodiment, they also maybe moved at the same time for shortening the time for expanding orcollapsing. For example, when expanding the barrel, after the firstgroup moving frame 3 starts moving and before it stops at apredetermined position, it may be possible to start moving the secondgroup moving frame 5 from the collapsed position and stop it at the wideangle end position (or a desired zooming position). Also, whencollapsing the barrel, after the second group moving frame 5 startsmoving and before it stops at a predetermined position, it may bepossible to start moving the first group moving frame 3 and stop it atthe collapsed position.

Moreover, although the present embodiment has illustrated an example inwhich the actuator 6 for driving the second group lens L2, the positiondetecting sensor 25 of the second group lens L2 and the driving gear 19for rotating the driving frame 15 are attached to the cam frame 17, thepresent invention is not limited to this configuration. Only theactuator 6 and the detecting sensor 25 or only the actuator 6 and thedriving gear 19 may be attached to the cam frame 17.

Second Embodiment

Hereinafter, a collapsible lens barrel in the second embodiment of thepresent invention will be described referring to FIG. 27. FIG. 27 is asectional view showing a cam frame 17 in the collapsible lens barrel ofthe present embodiment. The lens barrel of the present embodiment issimilar to that in the first embodiment except for what is describedbelow. The same elements as those in the first embodiment are given thesame reference signs, and the description thereof will be omitted.

FIG. 27 is a sectional view of the cam frame 17 taken along a planeperpendicular to the optical axis. On an outer peripheral surface of thecam frame 17, three cam grooves 18 a, 18 b and 18 c, a mounting portion17 a for a driving gear 19, a mounting portion 17 b for a drivingactuator 6 of a second group moving frame 5 and a mounting portion 17 cfor a home position detecting sensor 25 of a second group lens L2 areprovided alternately so as not to interfere with each other. Whenmolding this cam frame 17 out of a resin, it is necessary to combine aplurality of molding die parts to make one molding die, inject a resininto cavities in the molding die and, after resin-molding, pull out eachof the molding die parts in a predetermined direction so as to obtain amolded article.

Generally conceivable molding dies and molding method are as follows.Since the three cam grooves 18 a, 18 b and 18 c are provided atsubstantially 120° intervals, three molding die parts for molding thecam grooves 18 a, 18 b and 18 c respectively are used, and after theresin-molding, these molding die parts are pulled out radially in threedirections of A, B and C at 120° apart. Also, three molding die partsfor molding the three mounting portions 17 b, 17 c and 17 a respectivelyare used, and after the resin-molding, these molding die parts arepulled out radially in three different directions of D, E and F. Thus,in this method, it is necessary that at least six molding the partsrespectively corresponding to the three cam grooves 18 a, 18 b and 18 cand the mounting portions 17 a, 17 b and 17 c should be used for resinmolding and then pulled out radially in six different directions,thereby molding the cam frame 17.

In the present embodiment, the directions A and F for pulling out themolding die parts are made parallel with each other, thereby molding thecam groove 18 a and the mounting portion 17 c of the home positiondetecting sensor 25 of the second group lens L2 with one molding diepart. This reduces the total number of the molding die parts.

As described above, according to the second embodiment, since the numberof the molding die parts can be reduced when molding the cam frame 17,it is possible to suppress the cost of molding dies. This makes itpossible to reduce the cost of the collapsible lens barrel.

Although the above description has been directed to an example ofmolding the cam groove 18 a and the mounting portion 17 c with onemolding die part, the present invention is not limited to this. Bymolding at least one of the three cam grooves 18 a, 18 b and 18 c and atleast one of the mounting portions 17 a, 17 b and 17 c with a commonmolding die part, the effect described above can be obtained.

Third Embodiment

Next, a collapsible lens barrel in the third embodiment of the presentinvention will be described referring to FIG. 28. FIG. 28 is a sidesectional view showing an arrangement of a front end 6 b of a secondgroup lens driving actuator 6 in the collapsible lens barrel accordingto the present embodiment. The lens barrel of the present embodiment issimilar to that in the first embodiment except for what is describedbelow. The same elements as those in the first embodiment are given thesame reference signs, and the description thereof will be omitted.

FIG. 28 shows a non-capturing state similar to FIG. 22 in the firstembodiment. Unlike the first embodiment, in the present embodiment, agap 55 is provided between the first group lens L1 and the tubular firstgroup moving frame 3 in a direction perpendicular to the optical axis,and the front end 6 b of the second group lens driving actuator 6 entersthis gap 55 in the collapsed state.

In the configuration where the front end 6 b of the second group lensdriving actuator 6 is not made to enter this gap 55, it is necessary forthe second group lens driving actuator 6 to be disposed outside thefirst group moving frame 3 as in FIG. 22 of the first embodiment or thatthe second group lens driving actuator 6 should be disposed inside thefirst group moving frame 3 and at a position on a −Z direction side (onthe side of an imaging element 14). However, in the case where thesecond group lens driving actuator 6 is disposed outside the first groupmoving frame 3, an outer diameter of the collapsible lens barrelincreases. In the case where the second group lens driving actuator 6 isdisposed inside the first group moving frame 3 and at the positionshifted to the −Z direction side, the length L from the front end of thefirst group lens L1 to an end portion of the second group lens drivingactuator 6 on the side of the imaging element 14 increases. As a result,the entire length of the lens barrel 1 extends in the collapsed state.In contrast, according to the present embodiment, the outer diameter andthe length L can be reduced.

As described above, in accordance with the third embodiment, with theconfiguration in which the gap 55 is provided between the first grouplens L1 and the first group moving frame 3 in the directionperpendicular to the optical axis and the front end 6 b of the secondgroup lens driving actuator 6 enters the gap 55 in the collapsed state,it becomes possible to reduce the outer diameter of the lens barrel 1and shorten the entire length of the lens barrel 1 in the collapsedstate.

Fourth Embodiment

In the following, an optical instrument using a collapsible lens barrelin the fourth embodiment of the present invention will be describedreferring to FIG. 29. FIG. 29 is a block diagram showing a configurationof an actuator driving circuit in the optical instrument in the presentembodiment. The optical instrument of the present embodiment is similarto that in the first embodiment except for what is described below. Thesame elements as those in the first embodiment are given the samereference signs, and the description thereof will be omitted.

The actuator driving circuit in the present embodiment shown in FIG. 29is obtained by adding a zoom initial position storing system 53 to theactuator driving circuit in the first embodiment shown in FIG. 12. Thiszoom initial position storing system 53 is configured by a nonvolatilememory such as EEPROM or the like and stores as initial optical zoomingfactor information a zoom position immediately before turning off thepower after the completion of image capturing using the DSC 80. In otherwords, when the power source button 81 is turned off in any of thecapturing states shown in FIGS. 23, 24 and 25, the zooming positionimmediately before that is stored in the zoom initial position storingsystem 53.

Thereafter, when the power source button 81 of the DSC 80 is turned on,the first group lens driving actuator 22 for driving the first grouplens L1 rotates and shifts to the state shown in FIG. 23. Next, themicrocomputer 50 reads out the zooming position stored in the zoominitial position storing system 53 and, according to the read-out zoominitial position stored value, moves the second group lens L2 serving asa zooming lens to a predetermined position. For example, if the zoominitial position stored value corresponds to the state at the wide angleend, the second group moving frame 5 is moved to the state shown in FIG.24 so as to achieve a state ready for image capturing.

As described above, according to the present embodiment, even afterturning off the power of the DSC incorporating a lens ready for a highzooming factor, a set value of the zooming position before turning offis stored automatically. This is very useful for capturing images manytimes at the same angle of view.

It should be noted that a resetting function in which the initial valueof the zooming position automatically can be set to, for example, atelephoto end when a user presses down a reset button (not shown) in theDSC also may be provided.

Fifth Embodiment

In the following, an optical instrument using a collapsible lens barrelin the fifth embodiment of the present invention will be describedreferring to FIG. 30 and FIG. 31. FIG. 30 is a block diagram showing aconfiguration of an actuator driving circuit in the optical instrumentin the present embodiment, while FIG. 31 is a schematic view showing anoperating panel in a zoom initial position selecting system. The opticalinstrument of the present embodiment is similar to that in the firstembodiment except for what is described below. The same elements asthose in the first embodiment are given the same reference signs, andthe description thereof will be omitted.

The actuator driving circuit in the present embodiment shown in FIG. 30is obtained by adding a zoom initial position selecting system 54 to theactuator driving circuit in the fourth embodiment shown in FIG. 29. Theoperating panel in the zoom initial position selecting system 54 isprovided in an operating portion on an outer surface of a DSC 80 (seeFIG. 14), and its external appearance includes arrow keys 54 a forselecting a zooming position and a display portion 54 b for displaying acurrent zooming position by illumination as shown in FIG. 31. A userselects a zooming position by pressing down the arrow keys 54 a, therebyselecting freely the zooming positions after turning on the power. Theselected zooming position is stored in the zoom initial position storingsystem 53 as the initial optical zooming factor information.

When the power source button 81 is pressed down to turn on the power,the first group lens L1 moves to the position shown in FIG. 23 similarlyto the fourth embodiment described above. Subsequently, themicrocomputer 50 reads out the zooming position of the zoom initialposition storing system 53 set by the zoom initial position selectingsystem 54 and, based on this, the second group lens L2 moves andautomatically is set to the zooming position preset by a user.

As described above, in accordance with the present embodiment, thezooming factor at the time of turning on the power can be set freely bya user, thereby making it possible to change the zooming factordepending on the scene or situation of image capturing. Consequently, itis less likely that a problem of missing a shutter chance is caused.

It should be noted that the zoom initial position to be selected may bedesigned to be set continuously in the range from the wide angle end tothe telephoto end.

Sixth Embodiment

Next, a collapsible lens barrel according to the sixth embodiment of thepresent invention will be described with reference to FIGS. 32 and 33.FIG. 32 is an exploded perspective view for describing a positionalrelationship between the driving gear 19 and the image blurringcorrecting device 31 in the collapsible lens barrel in the presentembodiment, while FIG. 33 is a front view, seen from a directionparallel with the optical axis, showing the driving gear 19 and theimage blurring correcting device 31 in the collapsible lens barrel inthe present embodiment. The lens barrel of the present embodiment issimilar to that in the first embodiment except for what is describedbelow. The same elements as those in the first embodiment are given thesame reference signs, and the description thereof will be omitted.

Referring to FIG. 32, a mounting position of the driving gear 19 will bedescribed.

The driving gear 19 transmits a driving force of the reduction gear unit21 attached to the master flange 10 to the driving frame 15 and needs tohave a predetermined length along the optical axis direction for themoving frame 15 to move in the optical axis direction. Also, in order tomove the moving frame 15 in the optical axis direction, the cam frame 17is provided with the cam grooves 18 a, 18 b and 18 c, and it isnecessary that the driving gear 19 should be attached to the cam frame17 so as not to interfere with the cam grooves. Furthermore, the imageblurring correcting device 31 is provided between the master flange 10and the cam frame 17. Due to such restrictions, the driving gear 19 isdisposed between the two electromagnetic actuators 41 y and 41 x thatare placed at positions at 90° to the optical axis so as not tointerfere with the image blurring correcting device 31. As a result, thecam frame 17 is provided with the driving gear 19 and further with thecam grooves 18 b and 18 c on both sides thereof, so that in thecollapsible lens barrel 1 having the image blurring correcting device31, the driving gear 19 can be disposed near to the center of theoptical axis without causing interference between the image blurringcorrecting device 31 and the driving gear 19 for collapsing.

Furthermore, as shown in FIG. 33, the driving gear 19 is disposedbetween the two electromagnetic actuators 41 y and 41 x, so that thethird group frame 8 on which the image blurring correcting device 31 ismounted fits substantially within a circle of the cam frame 17 indicatedby a double-dashed line. Accordingly, the diameter of the collapsiblelens barrel 1 can be reduced.

As described above, according to the present embodiment, by providingthe driving gear 19 for collapsing between the two actuators 41 y and 41x for correcting image blurring, the driving gear 19 can be brought nearto the center of the optical axis without causing interference with thecam grooves. Consequently, it is possible both to shorten the entirelength of the lens barrel and to reduce the diameter thereof.

Seventh Embodiment

Now, a collapsible lens barrel according to the seventh embodiment ofthe present invention will be described referring to FIG. 34. FIG. 34 isan exploded perspective view for describing a positional relationshipbetween the shutter unit 24 and the second group moving frame 5 in thecollapsible lens barrel in the present embodiment. The lens barrel ofthe present embodiment is similar to that in the first embodiment exceptfor what is described below. The same elements as those in the firstembodiment are given the same reference signs, and the descriptionthereof will be omitted.

Referring to FIG. 34, where to place driving actuators 24 a and 24 b ofthe shutter unit 24 will be described.

The shutter unit 24 includes the diaphragm blade and the shutter bladethat form a constant aperture diameter for controlling an exposureamount and an exposure time of the imaging element 14. The diaphragmblade is driven by the driving actuator 24 a, and the shutter blade isdriven by the driving actuator 24 b. The driving actuators 24 a and 24 bare provided so as to protrude from the surface of the shutter unit 24opposite to the image blurring correcting device 31, that is, thesurface on the side of the second group moving frame 5. In the surfaceof the second group moving frame 5 on the side of the shutter unit 24,recessed portions 5 d and 5 e are provided at two positionscorresponding to the driving actuators 24 a and 24 b. As a result, whenthe distance between the second group moving frame 5 and the shutterunit 24 decreases, the driving actuators 24 a and 24 b partially enterthe recessed portions 5 d and 5 e of the second group moving frame 5,respectively, thereby preventing the interference between the drivingactuators 24 a and 24 b and the second group moving frame 5.

Therefore, for example, when the clearance between the second group lensL2 and the image blurring correcting lens group L3 decreases at thetelephoto end shown in FIG. 23, a part of the driving actuator 24 a ofthe shutter unit 24 enters the recessed portion 5 d of the second groupmoving frame 5.

As described above, in accordance with the present embodiment, thedriving actuators 24 a and 24 b of the shutter unit 24 are provided onthe surface of the shutter unit 24 on the side of the second groupmoving frame 5, and the second group moving frame 5 is provided with therecessed portions that the driving actuators 24 a and 24 b partiallyenter. This can reduce the clearance between the shutter unit 24 and thesecond group moving frame 5, thereby shortening the entire length of thecollapsible lens barrel.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The embodimentsdisclosed in this application are to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, all changes that come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

1. A lens barrel comprising: a master flange having one side to which an imaging element and an electric substrate are attached; a cam frame fixed to the master flange; a first group moving frame that moves a first group lens relative to the cam frame in an optical axis direction; a shutter unit that is provided on the inner peripheral side of the cam frame; and a flexible print cable having one part connected to the shutter unit and the other part connected to the electric substrate on the imaging element side of the master flange.
 2. The lens barrel according to claim 1, wherein the cam frame fixed to the master flange with a screw from an imaging element side of the master flange. 